It has long been desired to maximize fuel economy, power and driveability in gasoline powered vehicles while enhancing acceleration, reducing emissions, and preventing hesitation. While it is known to enhance gasoline powered engine performance by employing dispersants to keep valves and fuel injectors clean in port fuel injection engines, such gasoline dispersants are not necessarily effective for cleaning up direct fuel injected engines. The reasons for this unpredictability may lie in the many mechanical and operational differences between the direct and port fuel injected engines and the fuels suitable for such engines.
With the current use of direct fuel injected gasoline engines, dispersants that previously could have been used for gasoline engines do not work for both direct injected engines and port fuel injected engines. For example Mannich dispersants that were used in port fuel injected gasoline engines fail to provide suitable improvement in direct injected gasoline engines.
Over the years, dispersant compositions for gasoline fuels have been developed. Dispersant compositions known in the art for use in fuels include compositions that may include polyalkylene succinimides, polyalkenepolyamines, polyetheramines, and polyalkyl substituted Mannich compounds. Dispersants are suitable for keeping soot and sludge suspended in a fluid, however dispersants are not particularly effective for cleaning surfaces once deposits have formed on the surfaces. Fuel compositions for direct fuel injected engines often produce undesirable deposits in the engine combustion chambers, fuel supply systems, fuel filters, etc. Accordingly, improved compositions that can prevent deposit build up, maintaining “as new” cleanliness for the vehicle life are desired. Ideally, the same composition that can clean up dirty fuel injectors restoring performance to the previous “as new” condition would be equally desirable and valuable in the attempt to reduce air borne exhaust emissions and to improve the power performance of the engines.
Some additives, such as quaternary ammonium salts that have cations and anions bonded through ionic bonding, have been used in fuels but may have reduced solubility in the fuels and may form deposits in the fuels under certain conditions of fuel storage or engine operation. Also, such quaternary ammonium salts may not be effective for use in fuels containing components derived from renewable sources. Accordingly, there continues to be a need for fuel additives that are effective in cleaning up fuel injector or supply systems and maintaining the fuel injectors operating at their peak efficiency.
In accordance with the disclosure, exemplary embodiments provide a method for improving performance of fuel injectors, and a method for cleaning fuel injectors for an internal combustion engine. The methods include operating the engine on a fuel composition comprising a major amount of fuel and from about 1 to about 200 ppm by weight based on a total weight of the fuel of a reaction product of (i) a hydrocarbyl substituted compound containing at least one tertiary amino group and (ii) a halogen substituted C2-C8 carboxylic acid, ester, amide, or salt thereof, wherein the reaction product as made is substantially devoid of free anion species.
A further embodiment of the disclosure provides a method of operating a fuel injected gasoline engine. The method includes combusting in the engine a fuel composition comprising a major amount of fuel and from about 1 to about 200 ppm by weight based on a total weight of the fuel of a reaction product of (i) a hydrocarbyl substituted compound containing at least one tertiary amino group and (ii) at least one halogen substituted C2-C8 carboxylic acid, ester, amide, or salt thereof, wherein the reaction product as made is substantially devoid of free anion species.
An advantage of the fuel additive described herein is that the additive may not only reduce the amount of deposits forming on direct fuel injectors, but the additive may also be effective to clean up dirty fuel injectors sufficient to provide improved engine performance.
Additional embodiments and advantages of the disclosure will be set forth in part in the detailed description which follows, and/or can be learned by practice of the disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.